<template>
  <div>
         <div>{{teacher.name}}</div>
    <div>{{teacher.age}}</div>
    <div>{{teacher.salary}}</div>
    <button @click="timeFly">过了一年</button>
   </div>
</template>
 
<script>
export default {

  data() {
    return {
            teacher:{
        name:"harry",
        age:28,
        salary:3000
      }
    };
  },
  watch: {
    "teacher.age"(newVal,oldVal){
      if(newVal ===40){
        alert(' 您该退休了' + '您现在的年龄是' + this.teacher.age + '您现在的工资是' + this.teacher.salary)
        }
        else {
          return oldVal
      }
    }
  },
  methods: {
        timeFly() {
      this.teacher.age += 1
      this.teacher.salary += 500
    }
  }
};
</script>

<style scoped>
     
</style>